With the development of mobile network, bandwidth of wireless network has become higher, and rich media applications grow accordingly. Rich media content such as audio and video often requires a fairly large amount of space and is highly dependent on support of content delivery system to ensure the user experience using these rich media applications under mobile networks. Existing centralized content delivery systems often deploy cache systems near users. By changing the forwarding of domain name, requests can be directed into the cache systems. Thus, content can be obtained from the nearby cache systems and less burden may be imposed on the source station. However, existing centralized content delivery schemes have certain shortcomings. For example, an existing centralized content delivery system is often susceptible to bottleneck issues when the amount of user requests is large, causing a decrease in availability and impaired user experience. In addition, the conventional centralized content delivery scheme may be susceptible to single point failure. Also, a centralized content delivery network scheme requires considerably high delivery cost.
Peer-to-peer (P2P) technology has become a considerably mature technology, and has been widely used for content delivery in fixed networks. P2P refers to point to point transmission of data, where the “point” here indicates a user terminal. In the conventional centralized content delivery system, a user can only obtain resources from the source station or the cache system. According to the P2P technology, a user can obtain data from another user terminal that already has the resources. Thus, distributed downloading of data can be implemented, and the shortcomings of the centralized content delivery system can be resolved.
If the P2P technology can be applied under mobile networks, the content delivery system under mobile networks can be more efficient. However, mobile networks and fixed networks are quite different, and the conventional P2P technology used in fixed networks is not suitable for mobile network applications. The reasons may be described in the following aspects.
Firstly, a mobile network has high delay and high amounts of network jitter, and is more unstable compared to fixed networks. In this situation, conventional P2P technology is not able to ensure the timely supply of data. For example, the initial packet is not timely sent out, and user experience cannot be effectively ensured.
Secondly, P2P often requires data sources (P2P technology refers to a data source as a seed) to be permanently online. However, a mobile terminal depends on battery power, and each mobile platform often restricts data usage of backstage applications to conserve power usage. Under such condition, seed service is not reliably guaranteed, and availability can be affected accordingly.
Further, mobile network carriers charge for mobile traffic use, and conventional P2P scheme is not able to distinguish between chargeable traffic and free traffic. As a result, a higher usage cost can be imposed on a user terminal.
Thus, a method and a system, capable of overcoming the abovementioned shortcomings and suitable for P2P content delivery of mobile smart terminal applications, are desired.